Figure 2. Alkane transport in kerogen-like nanoporous carbons.

Flow of different n-alkanes in nanoporous carbon under an external driving force −∇P: methane (black), propane (blue), hexane (green), nonane (yellow) and dodecane (red). (a) Linear response of the mean flow velocity to the pressure gradient (T=423 K, P=25 MPa, dashed lines: linear fits); (b) permeance K=−q/∇P as a function of the thermodynamic equilibrium pressure P. Values of the permeance K are in full agreement with equilibrium calculation based on Green–Kubo relationship, see Supplementary Fig. 5a. This demonstrates that the linear relationship obtained here pertains to small pressure drops relevant to experimental conditions.